Ch 15 Cell Walls

Question 1

1. The cell walls of bacteria are a copolymer of _______ and _______.
   a. proteins; lipids
   b. proteins; polysaccharides
   c. polysaccharides; peptides
   d. cellulose; lignin

Answer 1

polysaccharides; peptides

Question 2

2. Gram-positive bacteria have a
   a. thin cellulose wall between two membranes.
   b. thin peptidoglycan wall between two cell membranes.
   c. thick cellulose wall outside the plasma membrane.
   d. thick peptidoglycan wall outside the plasma membrane.

Answer 2

thick peptidoglycan wall outside the plasma membrane.

Question 3

4. Fungal cell walls are built primarily of
   a. cellulose.
   b. peptidoglycan.
   c. pectin.
   d. chitin.

Answer 3

chitin.

Question 4

5. The polysaccharide chains of the bacterial cell walls are made of alternating N-_______ and N-_______ acid.
   a. acetylgalactose; acetylmuramic
   b. acetylglucosamine; acetylmuramic
   c. acetylglucosamine; acetylneuraminic
   d. acetyl galactose; acetylneuraminic

Answer 4

acetylglucosamine; acetylmuramic

Question 5

6. Plant cell walls are cellulose fibrils in a matrix of
   a. chitin and pectin.
   b. pectin and hemicellulose.
   c. Pectin and lignin.
   d. lignin and chitin.

Answer 5

pectin and hemicellulose

Question 6

7. The structural polysaccharide of fungal cell walls is the same polysaccharide found in insect
   a. exoskeletons.
   b. endoskeletons.
   c. eyes.
   d. cartilage.

Answer 6

exoskeletons.

Question 7

8. Pectins form a _______ network in plant cell walls.
   a. fibrous
   b. gel-like
   c. solid, rigid
   d. waxy

Answer 7

gel-like

Question 8

9. Secondary cell walls are stronger than primary cell walls because secondary cell walls contain
   a. more pectin.
   b. less lignin.
   c. more chitin.
   d. layers of cellulose fibrils at various orientations to one another.

Answer 8

layers of cellulose fibrils at various orientations to one another.

Question 9

10. Cellulose synthase in plants is located
    a. in the Golgi apparatus.
    b. in the cytosol.
    c. in the plasma membrane.
    d. outside the cell.

Answer 9

in the plasma membrane

Question 10

11. The direction of cellulose microfibril synthesis in elongating plant cells is
    a. parallel to the direction of cell elongation.
    b. perpendicular to the direction of cell elongation.
    c. perpendicular to the direction of microtubules under the plasma membrane.
    d. parallel to the endoplasmic reticulum under the plasma membrane.

Answer 10

perpendicular to the direction of cell elongation.

Question 11

12. Which of the following statements about Gram-negative bacteria and Gram-positive bacteria is true?
    a. Only Gram-positive bacteria have a double layer of plasma membrane.
    b. Gram negative bacteria have much thicker cell walls than Gram-positive bacteria.
    c. Gram-positive bacteria have no plasma membrane, only a cell wall.
    d. Gram-negative bacteria are surrounded by a thin cell wall beneath an outer membrane.

Answer 11

Gram-negative bacteria are surrounded by a thin cell wall beneath an outer membrane.

Question 12

13. Gram-negative bacteria contain _______ which, when released into the bloodstream, cause fever, low blood pressure, and inflammation.
    a. chitin
    b. cellulose
    c. peptidoglycan
    d. lipopolysaccaride

Answer 12

lipopolysaccaride

Question 13

14. The principal component of the cell walls of both Gram-positive bacteria and Gram-negative bacteria is _______.
    a. chitin
    b. cellulose
    c. peptidoglycan
    d. lipopolysaccaride

Answer 13

peptidoglycan

Question 14

15. In plants, primary and secondary cell walls, though distinctly different, share all of the following molecules except
    a. cellulose.
    b. hemicelluloses.
    c. pectin.
    d. peptidoglycans.

Answer 14

peptidoglycans.

Question 15

16. The thin, sheetlike basal laminae are found
    a. under epithelia.
    b. in the cytoplasm just below the plasma membrane.
    c. in the extracellular space surrounding all eukaryotic cells.
    d. in between adjacent cells connected by gap junctions.

Answer 15

under epithelia.

Question 16

17. The major protein of the extracellular matrix of animal cells is
    a. keratin.
    b. fibronectin.
    c. collagen.
    d. chondroitin sulfate.

Answer 16

collagen

Question 17

18. Collagens commonly contain the three repeating amino acids: _______, proline, and _______.
    a. glutamine; hydroxyproline
    b. glycine; hydroxyproline
    c. glycine; hydroxylysine
    d. glutamine; hydroxylysine

Answer 17

glycine; hydroxyproline

Question 18

19. Basal laminae are a meshwork of fibrils composed primarily of type _______ collagen.
    a. I
    b. II
    c. III
    d. IV

Answer 18

IV

Question 19

20. Tissue cells are connected to the extracellular matrix by receptors that bind to an adhesive protein called
    a. fibronectin.
    b. aggrecan.
    c. integrin.
    d. lamin.

Answer 19

fibronectin.

Question 20

21. Integrins are
    a. transmembrane proteins.
    b. peripheral membrane proteins.
    c. components of the extracellular matrix.
    d. components of a desmosome.

Answer 20

transmembrane proteins.

Question 21

22. Integrins bind to
    a. collagen.
    b. fibronectin.
    c. laminin.
    d. All of the above

Answer 21

All of the above

Question 22

23. The smallest amino acid is
    a. glycine.
    b. proline.
    c. cysteine.
    d. asparagines.

Answer 22

glycine.

Question 23

25. The major cell surface receptor(s) responsible for the attachment of cells to the extracellular matrix is (are)
    a. hemidesmosomes.
    b. desmosomes.
    c. integrins.
    d. laminin.

Answer 23

integrins.